<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <button>按钮1</button>
    <button>按钮2</button>
    <button>按钮3</button>

    <script>
        // 获取节点
        let btnList = document.querySelectorAll("button")
        // 绑定事件
        // btn.onclick = function(){
        //     console.log("hello word")
        // }

        for(let i in btnList){
            btnList[i].onclick = function(){
                console.log("hello")
            }
        }
    </script>
</body>
</html>